Testing For The Presence Of Macromolecules Using The Tests

Sudan IV is used for testing for lipids, if in fact lipid is present, the reaction would produce a red/orange color as opposed to no change at all (negative reaction: Stays pink color). This solution of Sudan IV is soluble in lipids, but not in water. Benedicts solution is the test used for reducing sugars or glucose testing. The positive reaction for this test should show a red/brick color after being placed in boiling water for three minutes, but if a negative reaction occurs we will get blue color or no change at all.

Another test that we were introduced to was the iodine test, which is used to detect starch. A costive reaction would result in a blue/black color, where as a negative reaction would be an amber color. Then in order to find the remaining agents (peptide bonds) we used Beirut’s solution, a violet color is produced when there is a positive reaction. Where as a light blue color is produced in the negative reaction.

The overall goal of this experiment is to find three of the four macromolecules (proteins, lipids, carbohydrates) that you can find in everyday living organism.

These macromolecules are the chain like proteins, carbohydrates, and nucleic acid. These macromolecules are made of smaller units that are called monomers hat make up polymers of covalently boding the identical and/ or similar monomer building blocks. These monomers are repeating units serving as building blocks for the polymers. The macromolecules need these smaller units to help complete their own tasks.

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These monomers form the common polymers carbohydrates, lipids, and proteins. Carbohydrates and lipids provide energy and storage, where proteins act as transportation and the storage cells.

The negative and positive controls of the experiment would be that, if the solution changes color the hypothesis above would be correct, while if it has no change then the lull hypothesis would be true. The overall goal of this experiment was to discover the unknown molecule, with chemical testing. If the colors changes during the reaction then we would have a positive test in regards to the macromolecule that we are testing for. Methods: For the benedicts reducing sugars test, we obtained two groups of eight test tubes and numbered each set one threw eight.

For group one the Benedicts reducing sugars, we placed ten drops of onion juice test tube one along with ml of the Benedicts solution, test tube two is then filled with ten drops of potato juice and ml of benedicts solution, test tube three is filled with ten drops of sucrose solution followed by the additional ml of the benedicts solution, Test tube four is filled with ten drops of the glucose solution followed by an added ml of Benedicts solution, Test tube five is then filled with ten drops of distilled water with the benedicts solution (ml), test tube six is then filled with the reducing sugars solution ten drops as well along with the benedicts solution, tube seven will be for the ten drops of starch solution followed by the ml of benedicts solution, then for test tube eight this will be your unknown, there will e ml of the unknown and ml of the benedicts solution mixed in tube eight.

Then proceeded to place the eight test tubes into boiling water where they sat for 3 minuets, while we looked to see if there had been any color change. For the Iodine test for Starch, the same steps are taken to perform this test. You obtained eight test tubes, proceeded to number them numerically one threw eight. Once numbered, each individual test tube was filled with ten drops of one of the solutions as done in the benedicts test for reducing sugars test. So you will place ten drops of each individual solution into its own tube.

Solutions used as followed, test tube one ten drops of onion juice, test tube two ten drops of potato juice, test tube three ten drops of sucrose solution, test tube four ten drops of the glucose solution, test tube five will have ten drops of distilled water, test tube six will contain the reducing sugars solution, test tube seven is then filled with ten drops of starch, and test tube eight is also filled with the ml of the unknown solution. Then after we had filled the test tubes we added seven to ten drops of iodine then observed if there had been any color changes with the lotions.

The Beirut’s test for proteins we obtained six test tubes which then were labeled one threw six. Each individual test tube was given its own solution to be placed within in, test tube one contained ml of egg albumen, test tube two has ml of honey, test tube three has ml of amino acid solution, test tube four has ml of distilled water, test tube five contains ml of protein solution, and for test tube six it contained ml of the unknown corresponding to group C.

Each test tube then has 2. 5% sodium hydroxide (ml) to each tube, then we observed any color changes. The next test is the Lipid solubility in polar and monopole solvents test, for this experiment we obtained two test tubes. One of the test tubes we added ml of water and to the other we added ml of acetone, followed by the addition to both test tubes of a few drops of vegetable oil. Then observed the reaction and recorded the differences between the two. Following alone with the above stated test, the Sudan IV test for lipids was performed. We obtained six test tubes and labeled them one threw six, the sixth test tube being the unknown again.

Test tube one contains 1 ml of salad oil + eater, test tube two contains 1 ml of salad oil + Sudan IV solution, test tube three contains ml of honey + Sudan IV, test tube four will contain ml of distilled water + Sudan IV, test tube five will contain the unknown lipid + Sudan IV, then test tube six will contain the unknown agent that has been used in the previous tests performed. A simpler test we performed was the grease spot test for lipids, we obtained a piece of unglazed paper and proceeded to use an eyedropper and dropped a few drops of salad oil onto the paper. Then let the fluids evaporate, then if there were NY grease spots then we know that there is a lipid present. Results: The results for the benedicts test are as followed. For test tube one there was a positive reaction, the color had changed to brown-orange.

Test tube two had a negative reaction with the color remaining the same (blue), Test tube three,five, and seven all had a negative reaction as well, color still the same being an aqua blue . Test tube four, six, and eight had positive reactions. Leading us to find that the unknown control for group C is a sugar solution. The Bursts solution testing showed that test tube one changed to colors to light purple, test be two was a negative reaction being of dark yellow color, test tube three was also a negative reaction of light blue, test tubes four and six were negative as well. Although test tube five the protein solution tested positive with a color change of purple.

The Sudan IV test results of the test, were fairly the same as the rest, with only a few color changes. Test tube one had a clear color, where test tubes two and five both had dark pink colors. Tubes three and four were both light pink. The grease spot test for lipids also showed interesting reactions, the test tube with acetone dissolved the salad oil then separated the water from he acetone. (Acetone sank to the bottom). Then with the water drop the oil and water separated from one another, the oil staying on the surface. Discussion: The results of the experiments show what solutions contain which of the macromolecules that we were looking to find. (Proteins, lipids, carbohydrates).

Since some of the test results came back as a positive reaction, the hypothesis that if one of the macromolecules is present then there will be a positive test result, is proven true. Based on the data presented form the results of the test, it can be said that one can test for certain macromolecules using the Benedicts elution test, Bursts solution, Sudan ‘V, and the grease spot test to find one of the macromolecules such as a protein, lipid, or carbohydrates. In the benedicts solution test we found that if there was a positive reaction the color change is somewhere along the lines of a brick-red to a maroon brown, where the negative results was blue color.

Following that test the results for the bursts test were a purple for the positive reaction for the presence of a protein and a light blue for the negative reaction. Then for the Sudan IV reaction test, the results found that positive reaction would be neon pink color, and the negative reaction was a faded or light pink color. Then for the grease spot stain we found that in the presence of a lipid would be detected if there was a spot left on the unglazed paper after the liquid evaporated. In conclusion it can be said that testing for the presence of macromolecules using the above stated tests is a plausible way to find them, and a proven method based on the results found during the completion of the tests.